Processing workflow for the geometries of the protected areas managed by the World Database on Protected Areas (WDPA) and downloadable from Protectedplanet
The WDPA for October 2017 (IUCN / UNEP-WCMC, 2017) was downloaded and processed for purpose as follows, by Lucy Bastin and Andrea Mandrici at the Joint Research Centre of the European Commission, using the following protocol (Bastin & Mandrici 2017).
All archived data products are in lat/long EPSG:4326 projection, and area statistics have always been calculated using a Mollweide projection (EPSG: 54009).
1. Protected areas with point-only geometries and a reported area > 0 were given a circular geodesic point buffer with the reported area.
2. Polygon self-intersections were corrected in PostGIS, and point and line geometries resulting from the correction were discarded.
3. Polygons with only two coordinates (US ships) were converted to lines and buffered by a very small distance to create valid polygons.
4. Features at the dateline whose geometries fell outside legal coordinates were split, and the remaining part of the geometry translated to the correct side of the dateline.
5. Where a PA was divided into several parcels representing zones (separate records in the WDPA), these were aggregated to form a single union, so that WDPA ID is the unique identifier for the dataset. Any internal slivers and topological inconsistencies which resulted were repaired and removed. In these cases, parcel names, IDs etc have been concatenated in a comma-separated string to allow a single record for each PA.
6. To deal with duplicate PA IDs in the January 2017 WDPA, the ID for Polesye Valley of River Bug, Belarus has been changed to 555624313 (the wdpaid value for March 2017). The value assigned in January, (555587200) belongs to Pico de Tancítaro in Mexico.
7. As recommended by WCMC, the data was filtered to remove all features with a status of "not reported" or "proposed", and all features designated as UNESCO MAB Biosphere Reserves.
8. Protected areas with no polygon geometry were discarded, since it is meaningless to overlay the point buffers on physical data such as land cover.
9. The area in square kilometres was computed for each protected area, and only PAs with an area over 50 sq. km. were processed for DOPA indicators.
For the subset of protected areas described above, 10-kilometre buffers were produced as follows:
10. Polygons where any part of the PA or its buffer would cross the dateline were translated horizontally by 180 degrees to ensure correct buffering (This is because of issues with many buffering functions at the dateline, including the ESRI libraries available for use on Hadoop).
11. All polygons were processed on a Hadoop cluster to produce an external geodesic buffer of 10 km.
12. Polygons which had been translated in step 10, along with their buffers, were split as appropriate and moved back to their correct positions on the dateline.
13. Buffer areas were masked to eliminate areas which, although in the exterior buffer of a protected area, are covered by protection from another PA - i.e., to include only unprotected regions.
Additional citation information for raster products
14. The buffered PAs were rasterised individually to produce geotiffs with a background value of 0, a pixel value of 1 in the buffer and 2 in the PA itself. The resolution of these rasters is c. 100m at the equator, in a projection of EPSG:4326.
15. For masking purposes, a binary raster containing all PAs with polygon geometries (i.e., not derived point buffers) was produced in a lat-long projection (EPSG:4326). The resolution of this raster is c. 100m at the Equator.
The dataset should be cited as follows:
IUCN and UNEP-WCMC (2017), The World Database on Protected Areas (WDPA) [On-line], [January 2017], Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.
Post-processed by Lucy Bastin and Andrea Mandrici, Joint Research Centre of the European Commission: details available online at: https://dopa.wikispaces.com/WDPA+protected+Area+boundaries
IUCN and UNEP-WCMC (2017), The World Database on Protected Areas (WDPA) [On-line], [January 2017], Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.
Processing workflow for the geometries of the protected areas managed by the World Database on Protected Areas (WDPA) and downloadable from Protectedplanet
The WDPA for October 2017 (IUCN / UNEP-WCMC, 2017) was downloaded and processed for purpose as follows, by Lucy Bastin and Andrea Mandrici at the Joint Research Centre of the European Commission, using the following protocol (Bastin & Mandrici 2017).
All archived data products are in lat/long EPSG:4326 projection, and area statistics have always been calculated using a Mollweide projection (EPSG: 54009).
1. Protected areas with point-only geometries and a reported area > 0 were given a circular geodesic point buffer with the reported area.
2. Polygon self-intersections were corrected in PostGIS, and point and line geometries resulting from the correction were discarded.
3. Polygons with only two coordinates (US ships) were converted to lines and buffered by a very small distance to create valid polygons.
4. Features at the dateline whose geometries fell outside legal coordinates were split, and the remaining part of the geometry translated to the correct side of the dateline.
5. Where a PA was divided into several parcels representing zones (separate records in the WDPA), these were aggregated to form a single union, so that WDPA ID is the unique identifier for the dataset. Any internal slivers and topological inconsistencies which resulted were repaired and removed. In these cases, parcel names, IDs etc have been concatenated in a comma-separated string to allow a single record for each PA.
6. To deal with duplicate PA IDs in the January 2017 WDPA, the ID for Polesye Valley of River Bug, Belarus has been changed to 555624313 (the wdpaid value for March 2017). The value assigned in January, (555587200) belongs to Pico de Tancítaro in Mexico.
7. As recommended by WCMC, the data was filtered to remove all features with a status of "not reported" or "proposed", and all features designated as UNESCO MAB Biosphere Reserves.
8. Protected areas with no polygon geometry were discarded, since it is meaningless to overlay the point buffers on physical data such as land cover.
9. The area in square kilometres was computed for each protected area, and only PAs with an area over 50 sq. km. were processed for DOPA indicators.
For the subset of protected areas described above, 10-kilometre buffers were produced as follows:
10. Polygons where any part of the PA or its buffer would cross the dateline were translated horizontally by 180 degrees to ensure correct buffering (This is because of issues with many buffering functions at the dateline, including the ESRI libraries available for use on Hadoop).
11. All polygons were processed on a Hadoop cluster to produce an external geodesic buffer of 10 km.
12. Polygons which had been translated in step 10, along with their buffers, were split as appropriate and moved back to their correct positions on the dateline.
13. Buffer areas were masked to eliminate areas which, although in the exterior buffer of a protected area, are covered by protection from another PA - i.e., to include only unprotected regions.
Additional citation information for raster products
14. The buffered PAs were rasterised individually to produce geotiffs with a background value of 0, a pixel value of 1 in the buffer and 2 in the PA itself. The resolution of these rasters is c. 100m at the equator, in a projection of EPSG:4326.
15. For masking purposes, a binary raster containing all PAs with polygon geometries (i.e., not derived point buffers) was produced in a lat-long projection (EPSG:4326). The resolution of this raster is c. 100m at the Equator.
The dataset should be cited as follows:
IUCN and UNEP-WCMC (2017), The World Database on Protected Areas (WDPA) [On-line], [January 2017], Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.
Post-processed by Lucy Bastin and Andrea Mandrici, Joint Research Centre of the European Commission: details available online at: https://dopa.wikispaces.com/WDPA+protected+Area+boundaries
References:
Bastin, L, and Mandrici, A (2017) WDPA processing workflow description. Available online at: https://dopa.wikispaces.com/WDPA+protected+Area+boundaries
IUCN and UNEP-WCMC (2017), The World Database on Protected Areas (WDPA) [On-line], [January 2017], Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.